Fire tube and water tube boilers designed for commercial and industrial applications have two or more heavy duty drums or headers (collectively referred to herein as vessels) interconnected with numerous steel boiler tubes in the range of 2–3 inches in diameter. The boiler tubes are inserted through openings in the boiler vessel, welded to the exterior periphery of the vessel, expanded against the circumference of the openings, and flared or beaded against the vessel on the inner periphery of the openings. Over the life of the boiler, the boiler tubes may be removed and replaced up to five or six times incident to either repair or routine maintenance.
Boiler tube removal is usually achieved by cutting off the tubes close to the exterior periphery of the boiler vessel, heating and/or notching the tube stub with a torch, and forcibly driving the tube out of engagement with the vessel. This typically damages the boiler vessel openings, which must then be repaired before installation of replacement boiler tubes. Another possible technique, described in the U.S. Pat. No. 5,974,642 to Weeks et al., is to use a special purpose cutting tool to slit the boiler tube stub throughout its entire length and thickness, and then radially compress the tube end to close the slit and force the tube walls out of engagement with the boiler vessel opening, whereafter the tube stub is withdrawn from the opening. While this technique adequately addresses the problem of tube removal damage, it necessarily involves a considerable expense for the special purpose cutting tools, and has not gained widespread acceptance in the boiler repair industry. Accordingly, what is needed is a simple and cost-effective way of removing boiler tubes without causing boiler vessel damage.